// Copyright (c) Matthias Koch
//
// See the NOTICE file distributed with this work for additional information
// regarding copyright ownership.  rubicon licenses this file to you under 
// the Apache License, Version 2.0 (the "License"); you may not use this 
// file except in compliance with the License.  You may obtain a copy of the 
// License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software 
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the 
// License for the specific language governing permissions and limitations
// under the License.
// 
using System;
using System.Collections;
using System.Collections.Generic;

using XValidation.Exceptions;

namespace XValidation.Validations
{
  public class NotEmptyValidation : IValidation
  {
    private readonly Type[] _expectedTypes = new[] { typeof (IEnumerable), typeof (string) };

    public virtual void Validate (object value, string paramName, IValidationContext context)
    {
      if (value is string)
        Validate ((string) value, paramName);
      else if (value is IEnumerable)
        Validate ((IEnumerable) value, paramName);
      else
      {
        throw new IncompatibleTypeException (_expectedTypes, paramName);
      }
    }

    private void Validate (string value, string paramName)
    {
      if (value == string.Empty)
        throw new StringNotEmptyValidationException (paramName);
    }

    private void Validate (IEnumerable value, string paramName)
    {
      var enumerator = value.GetEnumerator ();
      if (!enumerator.MoveNext ())
        throw new EnumerableNotEmptyValidationException (paramName);
    }
  }
}